The invention relates to a fused switch unit.
Fused switch units such as these as well as the fuse plugs and switching rockers used in such fused switch units are used in widely differing configurations in buildings, in both private and commercial buildings, in particular in buildings in which machines are electrically operated. Furthermore, it is possible to use fused switch units such as these as well as components, for example the switching rocker or the fuse plug directly on or in machine elements or housings, for electrical protection of electrically operated machines.
A fused switch unit having a switching rocker and a fuse link is known, for example, from DE 34 06 815 C2. Fused switch units such as these are used to interrupt the circuit of, and hence the electrical supply to, machines and appliances automatically when the current intensity or the power in the circuit exceeds a specific, fixed value. In order to match these values to the circumstances, in particular to the electrical machines and appliances or external presets, for example safety presets, fuse links which have different characteristic values can be inserted into the fused switch units, or into the fuse plug.
Fused switch units such as these are also used, in particular, to reliably interrupt the circuit manually, in particular when it is necessary to carry out repairs on electrical appliances and machines. To this end, the switching rocker or the fuse plug is moved to its switched-off position together with the corresponding fuse link, which is mounted in a housing of the fused switch unit such that it can pivot between a switched-on position and a switched-off position. The circuit is thus interrupted so that it is possible, in particular, to carry out repairs safely to electrically operated machines and appliances.
However, there is a risk of the switching rocker or the fuse plug being moved accidentally from its switched-off position to the switched-on position, for example as a result of the elements having been set inaccurately and being in an intermediate position from which they drop back again to the switched-on position, or because a third party accidentally bumps against the apparatus or deliberately moves it to the switched-on position because he or she has not been informed that repairs are possibly still being carried out and that there is a possible hazard.
One object of the invention is thus to provide a fused switch unit which allows the switch plug to be protected easily and reliably in its switched-off position. In particular, it is in this case intended to be possible to use conventional apparatuses, which are not matched to a specific fused switch unit, and particularly also standard conventional interlocking apparatuses which are not related in any way to a fused switch unit, for this purpose.
This object is achieved by a fused switch unit according to the invention.
In order to protect the fuse plug in its switched-off position, the fuse plug is withdrawn from its operating position in the fused switch unit until the through-opening of the fuse plug is aligned with the through-opening in the fused switch unit or in a component of it, or the two through-openings overlap to such an extent, that an interlocking apparatus, for example a standard conventional padlock or a lead sealing wire, can be inserted through the two through-openings.
The fuse plug can be withdrawn from its operating position only in the switched-off position, since the fuse plug is otherwise held in its operating position by housing parts of the fused switch unit.
The expression xe2x80x9coperating positionxe2x80x9d of the fuse plug means that position in which the fuse plug can still be pivoted between its switched-on position and its switched-off position, possibly in the switching rocker. The fuse plug is then no longer in its operating position when it is withdrawn from the fused switch unit or from the switching rocker to such an extent that it is no longer to pivot it to its switched-on position, since area elements of the fuse plug abut against housing parts of the fused switch unit.
It is thus possible, according to the invention, to use standard conventional interlocking apparatuses, for example conventional padlocks or lead sealing wires or the like, for interlocking. There is no need for specially produced interlocking apparatuses, which fit only selected fused switch units. There is thus no need to stock different interlocking apparatuses for different fused switch units. This is also helpful for the private area, since non-commercial users do not normally have special interlocking apparatuses.
Switching to the switched-on position is reliably prevented since the fuse plug must be withdrawn from its limit position in order to fit an interlocking apparatus, and parts or areas of the fuse plug would then abut against the housing of the fused switch unit. The interlocking apparatus accordingly secures the switch plug in a longitudinal position in which it is pushed out of the operating position in the fused switch unit.
The through-openings in the fuse plug and in the fused switch unit, or in its components (for example the switching rocker) preferably have an essentially congruent cross section. This results in the two through-openings overlapping completely, so that an interlocking apparatus can be inserted without any problems through the through-holes. It is also possible to use interlocking apparatuses whose cross-sectional dimensions are matched to an identical cross section of the two through-openings, so that no axial play is possible between the fuse plug and the fused switch unit as soon as such an interlocking apparatus is inserted.
In one embodiment, the through-opening in the fuse plug is slightly smaller than the through-opening in the fused switch unit or in the switching rocker. Since the fuse plug is inserted into the fused switch unit or into the switching rocker, a certain amount of play between the fuse plug and the fused switch unit is essential for production reasons, as well as to avoid excessive friction, and hence wear. This therefore results in slight position fluctuations in a direction other than the insertion direction. A slightly smaller hole in the fuse plug thus means that the through-opening in the fuse plug can always completely overlap the through-opening in the fused switch unit even in the event of any possible deflection of the fuse plug, caused by play, in a direction other than the insertion direction.
It is also advantageous to provide insertion aids by the through-openings in the fuse plug and/or in the fused switch unit widening outward.
In one preferred embodiment, the through-openings in the fuse plug and in the fused switch unit do not overlap, or overlap only slightly, when the fuse plug is in its operating position. This makes it impossible to use objects of very small size as an interlocking apparatus, which can actually be inserted through any overlap which may possibly exist between the through-openings, for example caused by production tolerances, when the fuse plug is still in its operating position,
A fuse plug preferably has a holding area, which lies against a housing, in particular against a positioning apparatus on the housing, as soon as the openings are aligned, or at least partially overlap. In particular, such a holding area is designed such that it interacts with the housing, or with the positioning apparatus on the housing, in order to reliably hold the fuse plug or the switching rocker in its switched-off position. It is advantageous to design this holding area such that a reliable holding function is still provided even after a large number of operations and after the possible occurrence of wear, in particular erosion.
The holding area is composed, in particular, of a part of a side wall of the retaining area for a fuse link. This thus avoids additional design measures, keeping the component costs low.
The housing of the fused switch unit preferably has stop surfaces for the switching rocker and/or the fuse plug, against which both components lie when the switching rocker is in the switched-on position or switched-off position. These stop surfaces assist reliable positioning of the switching rocker or of the fuse plug, so that this also reduces the risk of incorrect positioning or incorrect operations.
In one embodiment, the housing of the fused switch unit has a positioning apparatus against which the holding area of the fuse plug lies as soon as the through-holes in the fuse plug and in the fused switch unit overlap. The stop surface for the fuse plug and the positioning apparatus on the housing are preferably designed in a standard manner. This refinement likewise avoids the risk of incorrect operation, and a long life is